scholarly journals Liquid Inclusion Collision and Agglomeration in Calcium-Treated Aluminum-Killed Steel

2021 ◽  
Vol 8 ◽  
Author(s):  
Mauro E. Ferreira ◽  
Petrus Christiaan Pistorius ◽  
Richard J. Fruehan

This work addresses conflicting results in the literature regarding liquid inclusion agglomeration. To assess whether liquid calcium aluminates do agglomerate in liquid steel, laboratory experiments were performed: melting electrolytic iron, deoxidizing the melt with aluminum and subsequently calcium treating the deoxidation products (alumina and magnesia-alumina spinel inclusions). Under laboratory conditions, solid spinels and alumina inclusions were successfully modified, producing a new population of much smaller calcium aluminate inclusions. The new population of inclusions forms because the presence of calcium in the liquid steel destabilizes alumina and MgO-alumina inclusions, which then dissolve into the melt. The liquid inclusions exhibited a weak but statistically significant tendency to agglomerate. Laboratory results were assessed in the light of different collision mechanisms. Agglomeration mainly occurs by Stokes and laminar fluid flow collision when no external stirring is imposed. Monte Carlo simulations of collisions agree reasonably well with experimental results. For industrial conditions, where the liquid steel is agitated by argon bubbling and/or electromagnetic stirring, turbulent collisions dominate.

1986 ◽  
Vol 18 (2) ◽  
pp. 151-156 ◽  
Author(s):  
R. Zapf-Gilje ◽  
S. O. Russell ◽  
D. S. Mavinic

When snow is made from sewage effluent, the impurities become concentrated in the early melt leaving the later runoff relatively pure. This could provide a low cost method of separating nutrients from secondary sewage effluent. Laboratory experiments showed that the degree of concentration was largely independent of the number of melt freeze cycles or initial concentration of impurity in the snow. The first 20% of melt removed with it 65% of the phosphorus and 90% of the nitrogen from snow made from sewage effluent; and over 90% of potassium chloride from snow made from potassium chloride solution. Field experiments with a salt solution confirmed the laboratory results.


2013 ◽  
Vol 805-806 ◽  
pp. 1716-1719 ◽  
Author(s):  
Gui Fang Zhang ◽  
Yue Hua Ding ◽  
Zhe Shi

A considerable number of research works have been carried out to study the effects of electric current and frequency of Electromagnetic Stirring (EMS) on the quality of cast steels, but there are only a few studies available addressing the effects of EMS location on inclusion removal and steel cleanliness An ideal position of EMS will improve inclusion floatation and separation from liquid steel. However, inappropriate installation will lead to the entrapment of the slag into liquid steel, and impact the quality of cast billet. The current applied for these plant trials was 300A at a frequency of 3Hz,positions form axial centers of EMS to the top of the mold were 450mm, 510mm and 690mm respectively . 130 billets of medium carbon steel were produced and samples were taken for spectral analysis to study the effects of installation location of EMS on steel cleanliness. The experimental results show that the optimum position of EMS should be placed 510mm from the top end of the copper mold when the electrical current is 300A at frequency of 3 Hz. The three parameters of placement of EMS in paper were obtained from the simulation results, and this paper focused mainly on the effect EMS position on inclusion behaviors in billet.


2020 ◽  
Vol 91 (11) ◽  
pp. 2000049 ◽  
Author(s):  
Maria Guadalupe González-Solórzano ◽  
Rodolfo Dávila Morales ◽  
Enif Gutiérrez ◽  
Javier Guarneros ◽  
Kinnor Chattopadhyay

2013 ◽  
Vol 59 (No. 1) ◽  
pp. 16-22 ◽  
Author(s):  
M. Müller ◽  
P. Hrabě

We evaluated a degree of the machine part abrasive wear with secondary focus on their hardness. The paper states laboratory results of overlay systems from their wear resistance point of view. Laboratory experiments were carried out by two-body abrasion on bonded abrasive of a P120 granularity. The results proved an increased abrasive wear resistance of martensitic, ledeburitic and stellitic overlays against eleven different original products. The overlay UTP Ledurit 60 reached the optimum values. The GD-OES (Glow Discharge Optical Emission Spectroscopy) method proved the different chemical composition of the overlay from the stated chemical composition of the overlaying electrode.    


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